His brother Nasser appeared with two other British men - 20-year-old Reyaad Khan, from Cardiff, and Abdul Raqib Amin, who grew up in Aberdeen.

In April, the Metropolitan Police issued a plea for people to come forward with information about their family members if they were concerned about them joining terrorist training camps in Syria.

And a British Jihadi who claims he is fighting alongside militants in Syria has said he will return to the UK when he sees 'the black flag of Islam' hanging over Buckingham Palace.

The man, who called himself Abu Osama, said he had been taking part in military training, making bombs and fighting with the extremist Al-Nusra Front, which is linked to al Qaida, for the past year.

Osuma, whose accent suggested he comes from the north of England, claimed to have been fighting for the establishment of a caliphate - which he referred to by the Arabic term Khilafah - across the Islamic world.

He told BBC 5 Live's Nicky Campbell: 'There is nothing in Britain - it is just pure evil.

'If and when I come back to Britain it will be when this Khilafah - this Islamic state - comes to conquer Britain and I come to raise the black flag of Islam over Downing Street, over Buckingham Palace, over Tower Bridge and over Big Ben.'